Modular head lamination device and method

ABSTRACT

A composite item is fabricated with a device. The device includes and end effector and a positioning device. The end effector places a tow. The end effector includes a spindle, compaction device, and a path. The spindle detachably secures a spool of tow and the path is disposed from the spool to the compaction device. The positioning device positions the end effector. The end effector is detachably secured to the positioning device.

FIELD OF THE INVENTION

The present invention generally relates to a lamination device. Moreparticularly, the present invention pertains to a system and device for,and method of, fabricating a composite item.

BACKGROUND OF THE INVENTION

Composite items are typically constructed from layers of material thatare laminated together. The categories of materials utilized tofabricate or ‘layup’ composite items includes, for example: fiber;fabric; tape; film; and foil. Within each of these categories, amultitude of diverse materials are utilized. For example, fibersutilized includes: glass; carbon; aramid; quartz; and the like. Whenthese fibers are arranged as woven sheets and unidirectional ribbons,they are referred to as fabric and tape, respectively.

Fiber placement is a process used to construct or fabricate compositeitems. These composite items include relatively simple planar sheets orpanels to relatively large complex structures. The composite items aregenerally built up from multiple layers or plies of composite materialsthat are pre-impregnated with uncured resin (“prepreg”).

A head on a seven-axis manipulator arrays a group of prepreg tows into acontinuous band and compacts them against the surface of a form or layuptool. Fiber placement combines the advantages of both filament windingand automated tape lamination while avoiding the disadvantages of each.Conventional fiber placement machines have a large refrigerated creelhouse used to store the composite prepreg material, or tow. This creelhouse is normally separated from the head and takes up to an hour torethread tows from the creel to the head when changing the material orthe head. In addition, resin often builds up on or around componentsthat carry the tow from the creel to the head and can cause downtime inproduction.

Accordingly, it is desirable to provide a method and apparatus capableof overcoming the disadvantages described herein at least to someextent.

SUMMARY OF THE INVENTION

The foregoing needs are met, to a great extent, by the presentinvention, wherein in one respect a device, system and method isprovided that in some embodiments places tow on a substrate with amodular head with integrated creel.

An embodiment of the present invention relates to a device to fabricatea composite item. The device includes and end effector and a positioningdevice. The end effector places a tow. The end effector includes aspindle, a tow path, and a compaction device. The spindle detachablysecures a spool of tow and the path is disposed from the spool to thecompaction device. The positioning device positions the end effector.The end effector is detachably secured to the positioning device.

Another embodiment of the present invention pertains to a system tofabricate a composite item. The system includes a tool, end effector,and positioning device. The tool includes a mandrel and a headstock. Atow is applied to the mandrel. The headstock rotates the mandrel aboutan axis. The end effector place the tow. The end effector includes aspindle, compaction device, and a path. The spindle detachably secures aspool of tow. The compaction device presses the tow upon the mandrel.The path is disposed from the spool to the compaction device. Thepositioning device operates cooperatively with the headstock to positionthe end effector relative to the tool and the end effector is detachablysecured to the positioning device.

Yet another embodiment of the present invention relates to a method offabricating a composite item. In this method, a first end effector isselected from a plurality of end effectors to apply a tow to a form. Thefirst end effector is secured to a positioning device and the tow isapplied to the form.

There has thus been outlined, rather broadly, certain embodiments of theinvention in order that the detailed description thereof herein may bebetter understood, and in order that the present contribution to the artmay be better appreciated. There are, of course, additional embodimentsof the invention that will be described below and which will form thesubject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of embodiments inaddition to those described and of being practiced and carried out invarious ways. Also, it is to be understood that the phraseology andterminology employed herein, as well as the abstract, are for thepurpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conceptionupon which this disclosure is based may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an automated lamination device accordingto an embodiment of the invention.

FIG. 2 is a perspective view of a front of an end effector that issuitable for use with the laminating device of FIG. 1.

FIG. 3 is a block diagram of a system suitable for use with thelaminating device of FIG. 1.

FIG. 4 is a system architecture for a controller suitable for use in thelaminating device of FIG. 1.

FIG. 5 illustrates steps involved in a method of placing tow tofabricate a composite item in accordance with the laminating device ofFIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention will now be described with reference to the drawingfigures, in which like reference numerals refer to like partsthroughout. As shown in FIG. 1, a laminating device 10 suitable for usein an embodiment of the invention includes a positioning device 12 andan end effector 14. The positioning device 12 is configured to positionor otherwise control the movement of the end effector 14. In anembodiment of the invention, the positioning device 12 is a roboticarmature or gantry-type positioning device configured to control threeto ten or more axes of movement. However, it is to be understood thatthe specific number of axes may depend upon the particular operatingcondition and thus, the number of axes controlled is not critical to theinvention.

The laminating device 12 is configured to fabricate an item 16 byapplying a course material 18 on a form 20. Typically, the item 16 isfabricated from multiple plies or layers of the course material 18. Invarious forms, the end effector 14 includes a compaction roller 22and/or sweep to apply the course material 18 to the form 20. The form 20is configured to provide a suitably stable and finished surface for plyplacement. As shown in FIG. 1, the form 20 is controlled to rotate aboutan axis. When controlled to rotate thusly, the form 20 is typicallyreferred to as a mandrel. In other embodiments, the form 20 may bestationary or controlled to move in various axes. For example, the form20 may be secured to a sliding table or X-Y table. In this regard, theseand other embodiments in which the form 20 and/or the end effector 14are controlled to move, one relative to the other, are within the scopeof the invention. Additionally, the movement of the form 20 and thepositioning device 12 both act to position the end effector 14.Furthermore, the movement of the form 20 and the positioning device 12is generally coordinated to such a degree that the devices operateessentially as a single unit and thus, for the purpose of thisdisclosure, modulation of the positioning device 12 and/or the form 20will be referred to with respect to the positioning device 12.Characteristics of the form 20, such as size, shape, contour, and thelike, are based upon design parameters of an item 16. The item 16 isshown in FIG. 1 being constructed from a plurality of courses 24. Eachlayer of the courses 24 that is placed upon the form 20 or a substrate26 is described as a ply and the item 16 is typically fabricated from aplurality of plies. The substrate 26 includes the form 20 surface and/ora previously applied course 24.

According to an embodiment illustrated in FIG. 1, the laminating device10 further includes an off-line station 28 configured to retain a set ofoff-line end effectors 30. The off-line end effectors 30 are eachoperable to be interchanged with the end effector 14 via a controllablequick release coupling. It is an advantage of various embodiments of theinvention, that the set of off-line end effectors 30 facilitate greatlyincreased productivity. That is, in the event that a servicing operationis to be performed upon the end effector 14, the end effector 14 isdisposed upon the off-line station 28 and taken ‘off-line’ bydisconnecting from the positioning device 12. The positioning device 12then connects to an off-line end effector 30 and the laminating devicecontinues to fabricate the item 16.

FIG. 2 is a perspective view of a front of the end effector 14 that issuitable for use with the laminating device 10. As shown in FIG. 2, theend effector 14 includes a set of spools 34 to dispense a tow 36. Thetow 36 includes any suitable course material. Examples of suitablecourse material include various fibers, films, foils, and/or the like.Particular examples of fibers include glass, aramid, carbon, and variousother fibers. The tow 36 includes individual fibers, bundles, cords,plaits, ribbons in the form of unidirectional “tape,” woven fabric,biaxial cloth and the like. In addition, the tow 36 may bepre-impregnated with a resin or other such binding substance. Tocontinue, each of the spools 34 is mounted on a respective spindle ortensioner 38. The tensioner 38 detachably secures the respective spool34 to the end effector 14 and includes any suitable tensioning devicesuch as, for example, a brake or motor to tension and otherwise modulatethe rate at which the tow 36 is dispensed. A specific example of asuitable tensioning device includes a belt that wraps around a portionof the circumference of the tensioner 38 and generates friction thatretards the rotation of the tensioner 38. The friction is modulated viathe action of a solenoid or servo acting upon the belt. In conventionalfiber placement systems, the end effector may move over a meter relativeto the creel and, as such, the tensioners must take up this slack. Incontrast, as embodiments of the present invention include the creel inthe end effector 14, there is little or no slack to take up. Thus, it isan advantage of various embodiments of the invention that tensioner 38may utilize a relatively simple, inexpensive, and reliable tensioningdevice as compared to tensioning devices required by conventional fiberplacement systems.

The end effector 14 further includes a path 40 for the tow 36 to followas it travels from the spool 34 to a compaction roller 22. The path 40includes a dancer roller 42 that dampens rapid changes in tow feedrates. The path 40 further includes a redirecting pulley 44 to guide thetow 36 into a cutting assembly 46. According to an embodiment, thedancer roller 42 and the redirecting pulley 44 are essentially fixed inangle relative to one another. Thus, the angle at which the tow 36 isintroduced to the redirecting pulley 44 remains substantially constanteven as the radius of the spool 34 decreases due to removal of the tow36. The dancer roller 42 further facilitates a smooth removal of the tow36 from the spool 34 and may further facilitate removal of an optionaltow backing 48, if present. The tow backing 48 or separator film, ifpresent, substantially prevents the tow 36 from adhering to itself whileit is on the spool 34 or in roll form. To remove the tow backing 48, theend effector 14 optionally includes a backing removal system. Thebacking removal system includes any suitable system operable to draw offthe tow backing 48 from the tow 36. Suitable backing removal systemsinclude take up spools or reels and the like. In a particularembodiment, the end effector 14 includes a vacuum nozzle 50 in fluidcommunication with a vacuum source and configured to generate sufficientsuction to draw off the tow backing 48.

From the redirecting pulley 44, the tow 36 is directed further along thepath 40 and past a series of optional components such as, for example,combs, cutting assemblies, clamps, dancers, idlers and the like.Thereafter, the tow 36 is directed to the compaction roller 22.

Depending upon material characteristics of the tow 36, it may beadvantageous to modulate environmental variable such as, for example,temperature, humidity, and the like. In addition, based on manufacturersspecifications and/or empirically derived date, the storage and/orapplication conditions may differ. In this regard, the end effector 14optionally includes a housing 52, environmental control assembly 58(shown in FIG. 3), heater 56 (shown in FIG. 3) and chiller 58 (shown inFIG. 3). As shown in FIG. 2, the housing 52 encloses the set of spools34 and thus, facilitates control over the environment in which the tow36 resides by substantially retaining and/or directing flow of airsupplied by the environmental control assembly 58. The housing 52includes an opening 60 for the compaction roller 22 to address the form20. In various embodiments, the housing is opaque, transparent, or atleast partially transparent. For example, to facilitate visualinspection of the set of spools 34 and other components of the endeffector 14, the housing 52 includes a translucent or substantiallytransparent material such as, acrylic, polycarbonate, polyethylene,lexan®, Plexiglas®, and the like.

According to an embodiment of the invention, the compaction roller 22 isoptionally configured to move along an axis “A” relative to the endeffector. The axis A is generally referred to as the compliance axis andallows the lamination device 10 to accommodate a slight (±1 to 20 mm)misalignment of the form 20 and/or unanticipated tow buildup on the form20. In this regard, a compaction roller subassembly 64 is slidablysecured to a pair of brackets 66. The compaction roller subassembly 64is urged toward the form 20 via the action of one or more pneumaticcylinders 68.

FIG. 3 is a block diagram of a system 70 suitable for use with thelaminating device 10. As shown in FIG. 3, the system 70 includes acontroller 72. The controller 72 is operable to execute computerreadable code. In this regard, the system 70 includes a set of computerreadable instructions or code 74. According to the code 74, thecontroller 72 is configured to access a file 76. This file 76 includesone or more of the following: a computer readable model of the compositeitem 16; a computer readable representation of the surface of the layupform or the form 20; a computer readable representation of the edges ofthe form 20; the thickness of the composite item 16; a source code basedupon at least one of the composite item 16 and the form 20; a set ofmovement instructions based upon the source code; data gathered whilelaying up the composite item 16; timestamp information; positionalinformation; identification numbers; and the like. The controller 72 isfurther configured to communicate across a network 78. The network 78 isoptionally included to provide additional data storage and/or processingcapabilities. In this regard, the network includes a database 80 and aserver 82. The database 80 is configured to store a copy of the code 74and/or file 76. The server 82 is configured to generate, store, andperform any suitable processing of the code 74 and/or file 76. In thismanner, composite items, such as the composite item 16, generated oncomputer aided design (CAD) machines such as the server 82, for example,may be forwarded to the laminating device 10. In addition, the server 82is operable, via the network 78, to forward updates for the code 74and/or file 76. In addition, the system 70 optionally includes a memory84. If present, the memory 84 is configured to store a copy of the code74 and/or file 76.

Also shown in FIG. 3 is a positioning device controller 86. Thepositioning device controller 86 is optionally included in the system 70depending upon the requirements of the various actuators and/or servomotors of the laminating device 10. That is, depending upon theparticular configuration of the laminating device 10, a plurality ofactuators and/or servo motors modulate the rotation, position, speed,direction, and the like of the various components of the laminatingdevice 10. More particularly, these actuators and/or servo motors of thepositioning device 12 are at least configured to modulate the variousaxes of the end effector 14 and/or laminating device 10. If present,parameters of the positioning device controller 86 are based upon thespecification of the various actuators, servos, and/or the controller72. The positioning device controller 86, if present, is configured tocontrol some or all of these actuators and/or servo motors. In addition,these actuators and/or servo motors are optionally operable to bemodulated by the controller 72 directly, and thus, the system 70 mayomit the positioning device controller 86.

In addition, the controller 72 is configured to modulate the pluralityof tensioners 38. For example, depending upon the speed, direction oftravel, turning radius, and the like, the controller 72 is configured toindividually control an amount of resistance each tensioner 38 offers.In this manner, each tow 36 is controlled. Similarly, the controller 72is configured to control the cutting assembly 46 and a set of clamps 90Ato 90 n. In this regard, the end effector 14 generally includes a cutterand a clamp 90A to 90 n for each tow 36. The controller 72 is configuredto control the cutting assembly 46 and clamps 90A to 90 n such thatindividual tows may be added or removed from the course 24 asappropriate.

The controller 72 is further configured to control a release 92. Therelease 92 secures the end effector 14 to the positioning device 12 in acontrollable and releasable manner. For example, release 92 includes anysuitable actuator operable to exert a force upon a bearing surface suchas a locking pin or the like. In this manner, the controller 72 isoperable to quickly and automatically detach from the end effector 14and re-attach to one of the set of off-line end effectors 30.

Optionally, the controller 72 is configured to control and/orcommunicate with a variety of other devices such as the environmentalcontroller 56, heater 56, chiller 58, a vacuum source 94, and the like.As described herein, the environmental controller 56 is optionallyprovided to modulate the environment within the housing 52. In thisregard, the environmental controller 56 is configured to receive signalsfrom a sensor 96 and, based on these signals, control an airconditioning (“A/C”) unit 98. The sensor 96 is configured to sense theenvironment within the housing 52 and generate a signal based on theenvironmental conditions. The A/C unit 98 is configured to direct a flowof conditioned air within the housing 52. The heater 56 is optionallyprovided to modulate the temperature of the course material 18. Thechiller 58 is optionally provided to reduce the temperature of thecutting assembly 46, the set of clamps 90A to 90 n, the path 40, andvarious other components such as, for example, restart rollers, and thelike. The vacuum source 94 is optionally provided to supply vacuum tothe vacuum nozzle 50.

The system 70, optionally, further includes a plurality of sensorsconfigured to sense the various suitable operating conditions orattributes of the laminating device 10. Examples of suitable attributesinclude some or all of the temperature of the tow 36, the temperature atthe location where the separator film 22 is separated from the tow 36(release point), feed rate and direction, material placement, backingintegrity, supply of tow 36, and/or the like.

FIG. 4 is a system architecture for the controller 72 suitable for usein the system 70. As shown in FIG. 4, the controller 72 includes aprocessor 100. This processor 100 is operably connected to a powersupply 102, memory 104, clock 106, analog to digital converter (A/D)108, and an input/output (I/O) port 110. The I/O port 110 is configuredto receive signals from any suitably attached electronic device andforward these signals to the A/D 108 and/or the processor 100. If thesignals are in analog format, the signals may proceed via the A/D 108.In this regard, the A/D 108 is configured to receive analog formatsignals and convert these signals into corresponding digital formatsignals. Conversely, the A/D 108 is configured to receive digital formatsignals from the processor 100, convert these signals to analog format,and forward the analog signals to the I/O port 110. In this manner,electronic devices configured to receive analog signals mayintercommunicate with the processor 100.

The processor 100 is configured to receive and transmit signals to andfrom the A/D 108 and/or the I/O port 110. The processor 100 is furtherconfigured to receive time signals from the clock 106. In addition, theprocessor 100 is configured to store and retrieve electronic data to andfrom the memory 104. Furthermore, the processor 100 is configured todetermine signals operable to modulate the positioning device controller86 and thereby control the various actuators and/or servo motors of thelaminating device 10 to exert a particular force and/or rotate to aparticular degree.

According to an embodiment of the invention, the processor 100 isconfigured to execute the code 74. Based on this set of instructions andsignals from the various components of the laminating device 10, theprocessor 100 is configured to: determine a set of movementinstructions; modulate the heater 80, chiller 58, cutting assembly 46,and the like.

FIG. 5 illustrates steps involved in a method 120 of placing the tow 36to fabricate the composite item 16. Prior to the initiation of themethod 120, a composite product is designed and, based on this design, aseries of computer readable instructions specifying attributes of thecomposite product, such as the item 16, is generated. In addition,attributes or characteristics of the tow 36 are determined based uponcharacteristics of the item 16. For example, the item 16 may includelayers or plies of different composite materials. More specifically, anaircraft fuselage may include a multitude of carbon fiber plies toprovide structure, a wire mesh ply to protect against lightning, and asurfacing ply to provide a smooth surface. These different compositematerial may be separately loaded on to each of the set of off-line endeffectors 30 and, when appropriate, the respective off-line end effector30 is selected and utilized to place the tow 36. These and other suchparameters are included in the file 76 that contains the computerreadable instruction and is accessed to fabricate the item 16.

Furthermore, estimates for when one or more spool of the set of spools34 will be depleted are optionally calculated and, if it is determinedthat a spool is likely to be depleted during fabrication of the item 16,the set of off-line end effectors 30 may be configured to include areplacement. In this manner, downtime due to spool replacement may beminimized or essentially eliminated. Moreover, the set of off-line endeffectors 30 may be configured to include one or more spares to beutilized in the event of a malfunction. In this manner, downtime due tospool replacement may be further minimized or essentially eliminated.

In addition, a form or tool such as the form 20 is designed andconstructed based upon the design of the composite product. Furthermore,the spools 34 are installed in the end effector 14 and the tow 36 isthreaded through the end effector 14.

At step 122, the method 120 is initiated by powering or turning on thevarious components of the laminating device 10 described herein aboveand executing the computer readable instructions in the file 76.

At step 124, the system is checked to insure proper operation. Forexample, the controller 72 queries each of the components and, based onresponses from the components, the controller 72 determines theoperational status. The controller 72 may further determine the type ofcomposite material loaded on the end effector 14 and the supply of towon each of the set of spools 32.

At step 126 it is determined if the end effector 14 is appropriate andin working order. For example, the controller 72 accesses the file 76 todetermine if the composite material loaded in the end effector 14 isappropriate. If it is determined that the composite material is notappropriate, the end effector 14 is exchanged at step 128 with theappropriate off-line end effector 30. If it is determined that thecomposite material is appropriate, the tow 36 is applied at step 130.

At step 128 the end effector 14 is exchanged at step 128 with theappropriate off-line end effector 30. For example, the positioningdevice 12 positions the end effector 14 upon the off-line station 28 andcontroller 72 controls the release 92 to disengage. The positioningdevice is further controlled to select and couple with an appropriateoff-line end effector 30 and the controller 72 controls the release 92to engage. With regard to selecting the appropriate end effector, invarious embodiments, end effectors with particular types of tow may havepredefined positions on the off-line station 28 and/or the end effectormay be configured to determine the type of tow loaded therein and mayfurther be configured to determine its relative position upon theoff-line station 28. This information is forwarded to the controller 72and utilized to select the appropriate end effector from the set ofoff-line end effectors 30. In this manner, the end effector 14 isquickly and automatically exchanged thereby reducing or eliminatingdowntime due to at least changes in tow material, re-supply andthreading of tow material, and malfunction of the end effector 14.Following the step 128, a system check of the newly installed endeffector 14 is performed at step 124.

At step 130 the tow 36 is applied to the form 20. More particularly,according to the file 76, the controller 72 modulates the laminationdevice 10 to apply the tow 36 to the substrate 26. For example, a startlocation, path, and end location for a course is retrieved from the file76 and the controller 72 modulates the various components of thelaminating device 10 to tack the tow 36 to the start location, draw outand compact the tow 36 along the path, and cut the tow 36 at the endlocation.

At step 132 it is determined whether the layup for the item 16 iscomplete. For example, if the controller 72 determines an end of file(“EOF”) statement has been retrieved from the file 76, it is determinedthe layup of the item 16 is complete and the laminator 10 is controlledto idle until further instructions are received. If it is determinedthat further layup protocols are present in the file 76, it may befurther determined, at step 126, if the end effector 14 is operationaland supplied appropriately with the tow 36.

Following the method 120, the item 16 or composite product may be curedin any suitable manner. In the aerospace industry, thermoset resins aregenerally utilized to pre-impregnate ply material. These thermosetresins are typically cured at an elevated temperature and pressure for apredetermined amount of time. Times, pressures, and temperatures may beselected depending on the resin used, the size and thickness of thecomposite product, and the like.

Although an example of the end effector 14 is shown being controlled bythe positioning device 12, it will be appreciated that other controlsystems can be used. In this regard, a gantry system, guided vehicle, orother such positioning devices that support and control the movement ofany suitable end effector are suitable for use with end effector 14.Also, although the laminating device 10 is useful to place plies forcomposite products in the airline industry it can also be used in otherindustries that construct composite product. These industries include,but are not limited to, automobile, marine, spacecraft, building, andconsumer products.

The many features and advantages of the invention are apparent from thedetailed specification, and thus, it is intended by the appended claimsto cover all such features and advantages of the invention that fallwithin the true spirit and scope of the invention. Further, sincenumerous modifications and variations will readily occur to thoseskilled in the art, it is not desired to limit the invention to theexact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the invention.

1. A device to fabricate a composite item, the device comprising: an endeffector to place a tow, the end effector comprising: a spindle todetachably secure a spool of tow; a compaction device; and a path fromthe spool to the compaction device; and a positioning device to positionthe end effector, wherein the end effector is detachably secured to thepositioning device.
 2. The device according to claim 1, furthercomprising: a release being electronically controllable to secure anddetach the end effector and the positioning device.
 3. The deviceaccording to claim 1, further comprising: a plurality of interchangeableend effectors, wherein the positioning device is configured todetachably secure ones of the plurality of interchangeable endeffectors.
 4. The device according to claim 3, wherein the positioningdevice is configured to replace one of the plurality of interchangeableend effectors with another of the plurality of interchangeable endeffectors in about 20 seconds.
 5. The device according to claim 1,wherein the end effector is configured to dispense one or more of fiber,foil, pre-cut pieces of pre-preg, fabric, slit tape, tape, adhesivefilm, and surfacer film.
 6. The device according to claim 1, wherein thepath further comprises: a redirecting pulley; a clamp to substantiallystop movement of the tow; a cutting assembly to cut the tow; and arestart roller to feed the tow toward the compaction device.
 7. Thedevice according to claim 1, wherein the compaction device includes aroller to press the tow upon a substrate.
 8. The device according toclaim 1, wherein the compaction device includes a sweep to press the towupon a substrate.
 9. A system to fabricate a composite item, the systemcomprising: a tool comprising: a mandrel to apply a tow upon; and aheadstock to rotate the mandrel about an axis; an end effector to placethe tow, the end effector comprising: a spindle to detachably secure aspool of tow; a compaction device to press the tow upon the mandrel; anda path from the spool to the compaction roller; and a positioning deviceoperating cooperatively with the headstock to position the end effectorrelative to the tool, wherein the end effector is detachably secured tothe positioning device.
 10. The system according to claim 9, furthercomprising: a release being electronically controllable to secure anddetach the end effector and the positioning device.
 11. The systemaccording to claim 9, further comprising: an off-line station; and aplurality of interchangeable end effectors disposed upon the off-linestation, wherein the positioning device is configured to detachablysecure ones of the plurality of interchangeable end effectors.
 12. Thesystem according to claim 11, wherein the positioning device isconfigured to replace one of the plurality of interchangeable endeffectors with another of the plurality of interchangeable end effectorsin about 20 seconds.
 13. The system according to claim 9, wherein theend effector is configured to dispense one or more of fiber, foil,pre-cut pieces of pre-preg, fabric, slit tape, tape, adhesive film, andsurfacer film.
 14. The system of claim 9 further comprising, a vacuumsource; and a vacuum nozzle fluidly connected to the vacuum source andthe vacuum nozzle being configured to remove a backing from the tow. 15.The system of claim 9 further comprising, a take-up spool configured toremove a backing from the tow.
 16. A method of fabricating a compositeitem, the method comprising: selecting a first end effector from aplurality of end effectors to apply a tow to a form; securing the firstend effector to a positioning device; and applying the tow to the form.17. The method according to claim 16, further comprising: exchanging thefirst end effector for a second end effector of the plurality of endeffectors.
 18. The method according to claim 16, further comprising:accessing a file of computer readable instructions, wherein the computerreadable instruction call for application of a first type of towselected from a plurality of types of tows; and selecting the first endeffector in response the set of computer readable instructions, whereinthe first end effector includes the first type of tow.
 19. The methodaccording to claim 18, further comprising: disengaging the first endeffector from the positioning device in response to the computerreadable instruction calling for application of a second type of towselected from the plurality of types of tows; selecting a second endeffector from the plurality of end effectors in response to the set ofcomputer readable instructions, wherein the second end effector includesthe second type of tow; and securing the second end effector to thepositioning device.
 20. The method according to claim 16, furthercomprising: disengaging the first end effector from the positioningdevice in response to a supply of the first type of tow being below apredetermined amount of tow; selecting a third end effector from theplurality of end effectors in response to the first type of tow beingbelow the predetermined amount of tow, wherein the third end effectorincludes the first type of tow; and securing the third end effector tothe positioning device.
 21. The method according to claim 16, furthercomprising: disengaging the first end effector from the positioningdevice in response to a fault in the first end effector; selecting athird end effector from the plurality of end effectors in response tothe fault in the first end effector, wherein the third end effectorincludes the first type of tow; and securing the third end effector tothe positioning device.